	function accAdd(arg1, arg2) {  
        var r1, r2, m;  
        try {  
            r1 = arg1.toString().split(".")[1].length;  
        }  
        catch (e) {  
            r1 = 0;  
        }  
        try {  
            r2 = arg2.toString().split(".")[1].length;  
        }  
        catch (e) {  
            r2 = 0;  
        }  
        m = Math.pow(10, Math.max(r1, r2));  
        return (arg1 * m + arg2 * m) / m;  
    }   
    //减法函数  
    function Subtr(arg1, arg2) {  
        var r1, r2, m, n;  
        try {  
            r1 = arg1.toString().split(".")[1].length;  
        }  
        catch (e) {  
            r1 = 0;  
        }  
        try {  
            r2 = arg2.toString().split(".")[1].length;  
        }  
        catch (e) {  
            r2 = 0;  
        }  
        m = Math.pow(10, Math.max(r1, r2));  
         //last modify by deeka  
         //动态控制精度长度  
        n = (r1 >= r2) ? r1 : r2;  
        return ((arg1 * m - arg2 * m) / m).toFixed(n);  
    }  
    //乘法函数  
    function accMul(arg1, arg2) {  
        var m = 0, s1 = arg1.toString(), s2 = arg2.toString();  
        try {  
            m += s1.split(".")[1].length;  
        }  
        catch (e) {  
        }  
        try {  
            m += s2.split(".")[1].length;  
        }  
        catch (e) {  
        }  
        return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);  
    }  
    //除法函数  
    function accDiv(arg1, arg2) {  
        var t1 = 0, t2 = 0, r1, r2;  
        try {  
            t1 = arg1.toString().split(".")[1].length;  
        }  
        catch (e) {  
        }  
        try {  
            t2 = arg2.toString().split(".")[1].length;  
        }  
        catch (e) {  
        }  
        with (Math) {  
            r1 = Number(arg1.toString().replace(".", ""));  
            r2 = Number(arg2.toString().replace(".", ""));  
            return (r1 / r2) * pow(10, t2 - t1);  
        }  
    } 

	Number.prototype.add = function (arg) {  
        return accAdd(arg, this);  
    }; 
	Number.prototype.sub = function (arg) {  
        return Subtr(this, arg);  
    };
	Number.prototype.mul = function (arg) {  
        return accMul(arg, this);  
    };
    Number.prototype.div = function (arg) {  
        return accDiv(this, arg);  
    };  